Background: Ano-rectal disorders are common in the general population. Although they are not life threatening conditions, they do represent a social stigma and a reduced quality of life for the sufferer. The underlying physiology of muscle function contributing to ano-rectal competence is complex and there is room for a much better understanding so that treatments can improve.
Methods: A cylindrically shaped, liquid filled bag (12 cm long), mounted on a catheter was inserted into the anus and positioned straddling the ano-rectal region in 20 healthy volunteers (10 females). Series of volume-controlled distensions (40 mL min(-1) to 40 mL) were carried out and data on 16 CSA at 5 mm apart and bag pressure were recorded. Provocative tests using squeeze and cough at bag volumes of 20, 30, and 40 mL were carried out.
Key results: Ramp distension of the anal canal showed that the opening pressure for females (mean, 11 mmHg) was higher than for males (mean, 5 mmHg) (P < 0.001). Geometric profile of the anal canal at low distension volumes showed narrow bands at proximal and distal ends of the anal profile and shortening of a middle narrow zone at higher volumes. Inter-individual differences were observed in the behavior of the proximal end and the distal end of the anal profile during squeeze.
Conclusions & inferences: This distensibility technique provides an important new way of studying the anal canal and hence may have a role in testing sphincter competence in patients with disorders.
© 2012 Blackwell Publishing Ltd.